Further Mandelson documents to be published before Christmas, Cabinet Office says

The Cabinet Office has said that a number of further documents about Lord Mandelson's appointment as British ambassador to the United States will be published, likely before Christmas. Some papers will still be withheld at the request of the Metropolitan Police, which is investigating him.

The papers are being released in response to a humble address, a formal motion through which MPs ask the government for documents. In February, MPs voted to force the government to publish papers relating to the appointment. The motion was dated 4 February 2026.

Batches of papers were published in March and June. Others were held back because they formed part of the Metropolitan Police investigation. The force has said its inquiry into alleged misconduct in public office involving Lord Mandelson is ongoing. He was arrested on 23 February on suspicion of that offence. The investigation was launched over allegations that he passed market-sensitive government information to Jeffrey Epstein while serving as a government minister.

Cat Little, the permanent secretary at the Cabinet Office, the department's most senior civil servant, wrote to the chair of Parliament's Intelligence and Security Committee. She said the department had begun preparing the documents to be laid before the House in response to the humble address as soon as possible. She also said some withheld documents could now be published without prejudicing the police investigation.

According to Ms Little, the Mandelson documents will be reviewed and, in some instances, may be redacted, meaning parts are blacked out, to avoid prejudice to national security or international relations. The process is expected to be completed before Parliament rises for the Christmas recess on 17 December. She has also written to the chair of the Public Administration and Constitutional Affairs Committee about the publication process.

Lord Mandelson became British ambassador to the US in February 2025. He was dismissed in September, after Downing Street said new information about the extent of his relationship with Epstein had emerged. In February 2026, the government agreed a framework with the police on which documents relating to him could be released, according to Reuters.